The split nut compression fastener system is useful for easy application along with the ability to self-tighten as moisture content changes in wood, and to provide positive resistance against loosening caused by vibrations, flexing or seismic events. Although application in wood structures was the motivation for designing the fastener system the design has led to the realization that the system has a much wider range of applications. The fastener system can be scaled to fit any sized bolt or threaded rod simply by increasing the size of the exterior housing and interior lock threads. The fastener system has also been designed to where the user will not need to carry multiple wrenches or sockets for tightening. One size wrench or socket will be able to tighten multiple sizes of bolts before the exterior housing will adjust up to the next housing size. The steel version of the fastener system will hold against 50,000 lbf.
In the construction world there are many times during the work week when bolts or threaded rods are damaged during every day mishaps. This causes loss of time when hired employees go to install an average nut to damaged threads on a bolt or threaded rod. When threads get damaged, the employee will need to replace or repair the threaded surface before a nut can be applied. This results in higher a cost of construction.
Discovery of damaged threads on a threaded rod or bolt typically requires replacement for the rod. This sounds easy enough except when jobs are supplied with just the right amount of nuts and bolts for the job at hand. The result is the need for the employer or employee to travel to the nearest supply store to purchase a new bolt. Many bolts on construction sites are not in areas where they can be easily accessed from the ground. In fact, many bolts on construction sites are applied in high, off-the-ground setting, where the employees are in a man lift, using safety ropes and harnesses, or on a ladder. Additionally, many are actually threaded rods that may have been embedded in or under other components already, and therefore very difficult to replace. Damaged threads in these situations require the employee to get to the ground, retrieve another bolt, and return to the area to apply the new bolt. The other alternative is to try and use the damaged bolt which often will lead to cross threading. Tightening a cross threaded bolt results in a weak connection and a weakening of the structural connection. Weak connections equal a weak structure.
The fastener system can be used on every bolt to speed up installation or just on damaged bolts as needed. The fastener system can be slid over and by all damaged treads on a bolt, allowing installers avoid costly delays and frustrations. Most building procedures that require bolts also require heavy equipment to install the components that need to be bolted together. The fastener system installation will save time for the connection installer that will result in less costly equipment and equipment operator time.
Threaded rods are used to hold buildings to foundation, floor-to-floor connections, roof-to-building connections, and in retrofit remodel construction. When retrofitting or remodeling an existing building, extra connections are needed by adding threaded rod to existing foundations or side wall. Like bolts, some of the threaded rods get damaged and require extra time to repair. This involves getting tools to cut or grind on the threaded rod to repair the treads so that the nut can be applied. Threaded rods that are not repaired will also result in cross threading, which leads to weak connections.
The fastener system can be manufacture to fit any sized threaded surface. The fastener system in wood construction, where moisture content of materials may result in shrinking, may be used with a hold down or saddle. The fastener system application on wood structures will allow the nuts to self-tighten on bolts or threaded rods as the building materials shrink. The fastener system allows connections on wood to stay tight as the connection hardware was engineered to do. The fastener system in non-shrinking material is designed to be installed directly to raw surfaces and tightened.
Lumber may shrink significantly after construction installation. For example, a “2-by-10” board may be delivered to the job site at its nominal 9½ inch width by 1 9/16 inch thickness, but six months after installation it may be only 9¼ inches wide and 1 7/16 inches thick. Similarly, a “2-by-4” may be delivered to a job site at its nominal 1 9/16 inch thickness, but after six months it may have shrunk to 1 7/16 inches thick. While this can be problematic in any construction setting and must be accounted for, it creates special difficulties for installing seismic restraints and hurricane restraints, where significant shrinkage over time may render the bolted hold downs loose and ineffective. In other words, although conventional hold down systems may prevent a nut from backing off a threaded rod, they will not maintain the nut tight against the wood members as they shrink.
A number of devices have provided split nut capability, but lack the interchangeability, torque-taking ability, automatic tightening and damaged bolt capabilities of the present invention. Presently known art attempts to address this problem, but has not completely solved the problem.